A hydrocarbon conversion process in which the rate of coke formation is reduced without a significant sacrifice in light olefin and BTX yield by the use of a silylated, stabilized metal promoted zeolite catalyst. Another embodiment includes a novel silylated spinel/zeolite catalyst. Another embodiment includes a process for producing a zinc or gallium promoted zeolite in which the promoter is stabilized by a high temperature water vapor treatment in the presence of a metal oxide such as alumina and thereafter the stabilized catalyst precursor is calcined and silylated.